Alert archive / Oklahoma / Mesoscale Discussions in 2004

Mesoscale Discussion 425

April 21, 20048 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2004, 10:56 PM CDT for 8 counties in Oklahoma. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Apr 21, 2004, 10:56 PM CDT (03:56 UTC)
Expired: Apr 22, 2004, 12:30 AM CDT
In force: 94 min
Issued by: the Storm Prediction Center

Counties Alfalfa County, OK, Garfield County, OK, Grant County, OK, Kay County, OK, Kingfisher County, OK, Logan County, OK, Noble County, OK, Payne County, OK

The radar

The Vance AFB radar (KVNX), 53 km from the middle of the area, began a volume at 04:02 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 3.9 hours before the alert went out and 130 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 415 J/kg
Mixed-layer CIN: -82 J/kg
Mixed-layer LCL: 1340 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 120 m²/s²
0-3 km storm-relative helicity: 357 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 11.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 21, 7:06 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Beaver, Blaine, Dewey, Ellis, Harper and 3 more	2 hr
Apr 21, 7:51 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Blaine, Choctaw, Cleveland, Creek, Delaware and 18 more	84 min
Apr 21, 8:35 PM CDT	Severe Thunderstorm Watch	SPC	Alfalfa, Blaine, Dewey, Ellis, Garfield, Grant and 9 more	5 hr
Apr 21, 8:35 PM CDT	Tornado Watch	SPC	Atoka, Bryan, Choctaw, Coal, Haskell, Hughes and 6 more	5 hr
Apr 21, 10:10 PM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Craig, Creek, Delaware, Mayes and 8 more	95 min
Apr 21, 10:26 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Choctaw, Coal, Haskell, Hughes and 7 more	64 min
Apr 21, 10:50 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Cherokee, Craig, Creek, Delaware, Haskell and 14 more	5 hr
Apr 22, 1:43 AM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Haskell, McIntosh, Mayes, Muskogee and 7 more	92 min
Apr 22, 12:32 PM CDT	Mesoscale Discussion	SPC	Adair, Atoka, Cherokee, Coal, Delaware, Haskell and 15 more	88 min
Apr 22, 1:40 PM CDT	Tornado Watch	SPC	Adair, Atoka, Bryan, Carter, Cherokee, Choctaw and 33 more	6 hr
Apr 22, 3:26 PM CDT	Mesoscale Discussion	SPC	Adair, Atoka, Cherokee, Coal, Haskell, Hughes and 16 more	64 min
Apr 22, 4:30 PM CDT	Tornado Watch	SPC	Bryan, Love	6 hr
Apr 22, 5:27 PM CDT	Mesoscale Discussion	SPC	Adair, Atoka, Bryan, Choctaw, Coal, Craig and 23 more	63 min
Apr 22, 6:23 PM CDT	Mesoscale Discussion	SPC	Adair, Carter, Garvin, Hughes, LeFlore, McCurtain and 10 more	67 min

Nearby

Mesoscale Discussions in Oklahoma, 2004 Every mesoscale discussion in 2004

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.